The dark-gray traction current deposits belong to internal-tide deposits, it develops sandstones and siltsands, and charactered with lenticular, wave, flaser bedding, bimodal cross-bedding and ripple mark.

• 深水牵引流沉积为内潮汐沉积类型，岩性为细砂岩、粉砂岩，以发育透镜状、波状、脉状层理、双向交错层理、波痕等沉积构造为特征。